Underwater transmitter



F. M. MAYES Oct. 17, 1961 UNDERWATER TRANSMITTER Original Filed Jan. 10, 1951 3 Sheets-Sheet I.

INVENTOR. FRED M. MAYES BY W 3 4/ v 1 ATTYS Oct. 17, 1961 M. MAYES UNDERWATER TRANSMITTER Original Filed Jan. 1951 3 Sheets-Sheet 2 so 52 54 4s FIG INVEN TOR. FRED M. MAYES ATT YS.

F. M. MAYES Oct. 17, 1961 UNDERWATER TRANSMITTER 5 Sheets-Sheet 5 Original Filed Jan. 1 1951 FIGA.

ATTYS.

3,005,183 UNDERWATER 'IRANSMI'ETER TredM. Mayes, 614 Stockton Circle, Leedorn'Estates,

Ridleyiark, Original application Jan. 10, 1951, Ser. No. 265,396. Di-

rifled and this application June 25, 1957, Ser. No.

673,998 I 1 Claim. (1. 34ii6) (Granted underTitie 35, U.S.-Cde.(1952),.sec. 266) "This'invention relates to a method and apparatus for locating a naval ordnancedevice such as a torpedo, depth .chargeor thelike, which has sunk-to the bed of a'body .df water at the end of a practice or testing period.

This applicatiorrisa division oimy copending applica- :tion, Serial No. 205,396, filed January '10, (1951, vnow abandoned.

Several devices lhave.been"heretor"ore employedto re- ,cover practice torpedoes which have sunk to the'bottom at the .end ofiaipraetice g' st -i;*%iif,'%3%%e%8%f0%d to .be entirelysatisfactory under all conditions of service.

.Oneprior method employs a stream-linedfioat which" is towed-throughthe wateriby a' hoisting cable attached to theaftendofthe torpedo. IFrequent failure. in the use rofrthistmethod is caused by .twist-breakingtofthe. hoisting cableuduring :therpractice run andftherfloat produces a drag inthe waterwhichnmaterially reduces the speed of Jthe torpedo.

Another'locating apparatus Iheretdfore devised for a atorpedo-employsa float' having alengthof line attached ,tofthe torpe'doiwhichis initially enclosed within 'therhand- .iholevof the torpedo'by ai haudho1d.cover.. .Tl'hecover. is provided with a c0ntrol surface whichtis constructedsso that the kinetic pressure of the watercon thecontrol suriacevduring'the forward motion .of the torpedoholds thecover in theclosed position. When the torpedovcomes tozrest on-the bottom at theend of the practice run, .thekineticpressure on the control surface isrelieved and thecover flies open to allow the fioatto rise tovthe csurfaceto mark the location of the torpedo to aida diver .locating'the torpedoonthe bottom. Such a device .has not proven to be entirely satisfactory in servicebecause the cover opens if the torpedo-speedis. materially reduced and the line which connects 'thefloatto the torpedo vbecomes entangled .with the,propeller blades.

.According ,to the present invention an ultrasonic translmitteris dlSIJOSEdWithiH'. a torpedo handhole and operates .to transmit.intermittent sonic signalsin :the water .to 'radiateroutwardlyin all directions from the torpedoras .the torpedo rests .onthe bottom.

-A .recovery vessel carries .a directional hydrophone .zsubmerged within'the water and produces the maximum ;response to the transmitted signals from the torpedo when vthehydrophone-is pointed directly toward the transmit- ,ter. .The-vessel is-then steered on aecourseintheidirection indicated, by. the 1 hydrophone.

This a'itheemena dee aarrangedinia horizontal or. azimuth-searchin position.

:As-soon-as-the course of the searching vessel is established the hydrophone is rotated through 90 'to point the response area of the hydrophone toward the bed of the water. When 'the signal received reaches a maximum with thehydrophone pointed downwardly, the vesasel iscdirectly over the lost torpedoand an anchored marker buoy dropped to mark the location on the. surface tot thewater.

:Themextstep is for a diver to descend to thebottom adjacent thebuoy to exactly locate the torpedo and secure a hoistingrcable to the torpedo. The diver carries a gportabledirectional hydrophone similar to the hydrophone carried by the vessel which is connected to the Patented Oct. 11, 1961 12 earphones in'the diving'helmet'to allow'thediver to listen whilelhe seeks the torpedo withhisfhy'drophone. One of the objects of the present inveution'isto'pro vide a new and improved method and 'apparatus for 5 'locating a torpedo which has sunk to th e'bed of abou 'ofwater'atthe end of'a'practice or testing-period.

Another object is-to provide such a locating apparatus which will not interfere with the operation of thetorpedo during the testing period;

'Still another object'is'to provide'a new andyimproved mechanism 'for broadcasting sonic signals 'fronra torpedo "in" all 'directions'into the surrounding water "at the 'end of a practice or' test run. V

A still 'further' object is to provide' a sonicsignalbroadcasting-mechanism which may' befitteddntonthehan'd- ,hole of a torpedo.

Other objects andmanyof the-attendant advantages of this invention will be readily appreciated as the'same 'becomes better understood by referecne'to'thefollowing detailed deseriptioawhen considered in connestion vlith the accompanying drawings wherein:

FIG. 1 illustrates a diver 'employingaportable directionalhydrophone for locating a practice torpedo "which has sunk to'the bottom; ,FIG. ,2 is'a'sectionalview of thesoundemitting'mechanism which is fitted into thetorpe'do handholeprior' to "launching the torpedoon 'apractice-run;

'FIG. 3 is a transducerin section connected"t0i'the-( 1pcrating circuit employed in "connection 'withg'thepresent 3O invention for broadcasting: sound'signalsfrom thetorpefdo into the surrounding water; and V FIG. '4 'is the oscillating pcircuit, -schematica1lyil1ustrated, employed for energizingtthe transducer.

L'Referring now to, the drawings onwhichjlike. numerals are employed to designate like-parts throughoutthe' severalviews and more particularly to FIG. 1,' there is'fshown thereon a recovery vessellti fromwhichgadiverILhas .been lowere'd to seeka torpedo 12 which hassunk to the bottom at the end of'a pract'ice'run. Thediver'll carries a portable directional-hydrophom '13 connected electrically to earphones (not shown) en'close'dwvithin the helmet 14 of the 'diver. The portable hydrophone 13'fis adapted to receive the "maximum 'response when the flexible diaphragm 15 is pointed directly at thetorpedo 12 which broadcasts radiating sound signals into the surrounding water. 'Thejsound signalsbroadcasffromthe torpedo 12, originatefrom a transrnitter enclosed within ahan'dhole'lfi.

As "shown "2 the signal transmitter, generally designated 17, "comprises'a'tubuiar'cesinglfi t'elescopingly arranged within thetorpedo handhole 16. The bottom-end of casing 18 is sealed in watertightyrelation" by .a painof metallic disks '19 slidablyarranged Within'thercasing and having a rubher'ga'sket '21"disposedtherebetween which expands radially into watertight relationwith respectto the casing as the disks areforce'd toward eachotheras nuts22 damage tightened r mthesnaced rodslirjlheuppa npoitinnng casing 18 is providedwith aradial'flange'zii havingsuitable openings therethrou'gh for receiving bolts 33 which engage the usual threa'dedrecesses at the handhold'opening. An expansible gasket'dt) disposed between thefiange "29 and the han'dhole opening forms a watertight "seal 'therebetween'as the bolts "33 are tightened. A-metallic "cover-34, "formed'tofollow the contour of the torpedo exercise head, issecured to the flange 29 byset screws'SS. The spacer-rods 23 have-secured to themid-porti'on thereof a supporting-disk :24 which separates therosc'illator unit 25 from thepower'sourcecomprising the Abattery 26 and the B battery 27. Disk 24 is provided :with

- suitable insulated openings therethrough for receiving'con- .nector pins '6, 7. and 8 respectivelyfor electrically-connectingthe oscillator unit 25 .tottheibatterieszfit and '27.

Tie rods 5, extend through suitable openings in spacer rods 23 and have secured to the upper end thereof disk 4 for securing batteries 26 and 27 to prevent endwise movement thereof within the casing 18. The batteries 26 and 27 are provided with a centrally disposed opening 36 containing the insulated contact rod 37 which terminates with a spring terminal 39 which connects the oscillator unit 25 and transducer unit 32. The transducer unit 32, operated by the oscillator 25, is acoustically coupled to the cover 34 and casing 18 and produces sound signals which are thus transmitted through the surounding water in all directions from the torpedo as it rests on the bottom.

7 Referring now more particularly to FIG. 3 there is shown in section the transducer 32 suitable for the purpose comprising a non-magnetic housing 41 having a cylindrical end portion 42 closed in liquid-tight relation by a flexible cover 43, preferably rubber, which is secured to the end portion 42 in fluid tight relation by a pair of binding wires 44.

The housing 41 is provided with a threaded opening 45 containing an expansible gasket 46 disposed between a pair of washers 47. The gasket 46 seals the opening 45 as the non-magnetic pipe plug 48 forces the washers 47 toward each other as the plug is tightened in the opening 45.

. A conductor 51 is connected to a terminal 50 of an insulated rod 40 which is sealed in an opening through the pipe plug 48 and maintained in yieldable contact with spring terminal 39 thereof to form an electrical connection between the crystals 53 of transducer 32 and the oscillator unit 25. A second conductor 52, connected to alternate layers of foil 54, is grounded to housing 41 which, in turn, is grounded to the casing 18 when the transducer is assembled therein. The oscillator circuit may be of any well known pinging type which will preferably intermittently energize the transducer at 45 kc. Such an oscillator which is suitable for this purpose may be of the same general type as that disclosed in the copending application of Ford L. Johnson et al., Serial No. 657,310, filed March 26, 1946, for Distance Measuring Apparatus.

Disposed within the housing 41 are a pile of Rochelle salt crystals 53 with thin sheets of foil 54 separating the crystals from each other. The area between the crystals 53, casing 41 and cover 43 is entirely filled with castor oil. The crystals 53 are electrically connected to conductors 51 and 52 and are adapted to transform electrical pulses into pinging sonic pulses when operated by the oscillator circuit 25.

The pulsing oscillator circuit 25 is adapted to cause the crystal elements 53 to be driven intermittently at a predetermined rate such, for example, as 45 kc., the oscillator being operated from the batteries 26 and 27, thereby causing vibrations which are transmitted through the water as sonic pulses radiating in all directions from the torpedo.

The recovery vessel is provided with a searching device including a hydrophone which is mounted on the vessel. This hydrophone is used to bring the vessel directly over the lost torpedo at which point an anchored marker buoy is dropped from the vessel.

The next step is for the diver 11 carrying the portable hydrophone 13, to descend to the bottom adjacent the marker buoy. The hydrophone 13 is connected to suitable receivers and amplifiers (not shown) located on the search vessel and then to the earphones (not shown) enclosed within the helmet 14. The portable hydrophone will receive the maximum response from the transmitter 17 in the torpedo when the diaphragm of the portable hydrophone is pointed directly at the torpedo. Thus the diver, by following the maximum response in his earphones is guided to the submerged torpedo where a hoisting cable from the recovery vessel 10 may be attached to the torpedo.

Referring now to FIG. 4, there is disclosed therein a preferred type of pulsing oscillator circuit 25 which produces a large power output to the transmitter 32 and period of oscillation.

4 causes the generated signals to be transmitted over lon distances in the order of two miles while consuming only a small amount of power from the B battery. The circuit provides pulses of short duration compared with the interval between pulses, the duration of each pulse and tne interval therebetween being determined primarily by the time constants in the grid circuits. Stated in other words, the oscillator circuit generates oscillatory energy at predetermined spaced intervals of low duty cycle.

The oscillating circuit 25 comprises triode tubes 75 and 76, the plates of which are connected to the tuned circuit comprising condenser 77 and inductances 78 and 81 which principally determine the carrier frequency.

The plate 82 of tube 75 is coupled to the grid 83 of tube 76 by capacitor 84 and in like manner plate 85 and grid 86 are interconnected by capacitor 87, thereby providing the proper feedback for oscillation. The resistors 88 and 89 and capacitors 84 and 87 are of such value that blocking occurs due to grid rectification thereby cutting off the tubes for a fixed interval between each Resistor 88 may be made variable as indicated, if desired, to control the repetition rate of the pulses. The oscillating voltage generated in the plate circuit of tube 75 appears across inductance 81 and a portion of inductance 78. A substantial portion of this voltage exists across inductance 81 which provides a 7 coupling impedance to drive the transducer 32. In this manner it will be understood that a large portion of the oscillatory energy of the circuit is delivered to the transducer for transmission into the surrounding water.

The capacitance of the transducer 32 is dependent on temperature and to minimize this efiect condenser 79 is shunted across the transducer.

It will of course be understood that a similar transmitter may be disposed within a mine, depth charge, or other similar ordnance devices, to aid in locating these devices which have sunk to the bottom at the end ofa practice or test period. 5

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim: 7

In a system of the character disclosed, means for intermittently transmitting sound signals from a sunken torpedo having a casing with a handhole therein comprising, in combination, a tubular housing mounted within the handhole, an oscillating device mounted at the base of said housing, a cover enclosing said housing and acoustically connected to the torpedo casing, a transducer unit acoustically engaging said cover and adapted to transmit sound signals therethrough and through the casing when the transducer is operated, a battery having an opening therethrough and disposed within said housing between said transducer and said oscillating device, and a contact rod disposed within said battery opening and operatively connected to said oscillating device and said transducer whereby the transducer is operated from said oscillating device.

UNITED STATES PATENTS 2,641,780 Brown June 16, 1953 2 472 107 H l. 7 4 2,769,16 Miller 00L 30, 1956 2 499 23 s g fi 3:? 6, 1943 2,782,309 Aasma F611 19, 1957 2,499,520 Modlowski et a1. Mar. 7, 1950 2,803,807 Butler, 1957 2,517,138 Seabert Aug. 1, 1950 5 2,867,788 HETIY 1959 2,539,001 WincheI Jan. 23, 1951 2,869,108 Smlth 13, 1959 2,561,851 Fryklund July 24, 1951 2,938,483 Mason May 1950 2,629,053 De Boisblanc Feb. 17, 1953 

